Chatter switch



Jan. 24, 1961 H. H. HALL ErAL 2,969,440

CHATTER SWITCH Filed' June 8, 1945 Flag 3.

.4 I 45 +5 i 3| \5 38 l s4 Y d( L United States Patent CHATTER SWITCHHarry H. Hall, 1523 28th St. SE., Washington, D.C., and Whitney A.Brown, 15369 Tuller, Detroit, Mich.

Filed June 8, 1945, Ser. No. 598,351 2 Claims. (Cl. Z110-61.01) (Grantedunder Title 35, U.S. Code (1952), sec. 266) This invention relatesgenerally to chatter switches and more particularly to a chatter switchwhich is adapted to be set in operation in response to acoustic energyreceived thereby through an elastic medium, the principal object beingto provide a new and improved chatter switch having a novelconstruction, combination and arrangement o-f the parts thereof adaptedto receive, without damage thereto or operational impairment thereof,abnormally large amounts of energy sucn as may be received when theswitch is employed in mines, depth charges or the like.

Another object is the provision of a new and improved chatter switchresponsive to sound signals of predetermined frequency.

Another object is the provision of a new and improved chatter switchwherein means are provided for adjusting the sensitivity of the switch.

Still another object is to provide a new and improved chatter switch foruse in marine mines and wherein means are provided for substantiallyequalizing the static pressure head on the element in communication withthe surrounding water.

In accordance with the preferred embodiment of the present invention, apair of normally closed, Whisker type contacts are employed, one of thecontacts being carried by -a balance wheel mounted on a shaft androtatable therewith. Also mounted on the shaft is a resilient springmember which is adapted to exert tension on the shaft and balance wheelvariably in accordance with the setting of suitable adjusting meansprovided therefor. The other contact is secured to a post member whichin turn is clamped to a liexible diaphragm. The normally closed contactsare adapted to be disengaged at intervals as the diaphragm is set invibration by sound signals of sufficient strength to overcome thetension exerted on the balance wheel, such vibration being transmittedthrough the post member to the contact mounted thereon.

The invention, as well as additional objects and advantages thereof,will be best understood by referring to the following descriptionl takenin connection with the accompanying drawings wherein like referencecharacters refer to like parts throughout the several views and inwhich:

Fig. l is a sectional view of the device of the present invention;

Fig. 2 is a fragmentary sectional view taken substantially along theline 2 2 of Fig. l;

Fig. 3 is a sectional view taken substantially along the line 3-3 ofFig. 2;

Fig. 4 is a view in section taken substantially along the line 4-4 ofFig. 3;

Fig. 5 is a fragmentary view in section taken substantially along theline 5-5 of Fig. 3; and,

Fig. 6 is a fragmentary sectional view taken substantially along theline 6--6 of Fig. 3.

Referring now to the drawings for a more detailed description of theinvention and particularly to Figs. 1 through 6 inclusive, there isshown thereon a chatter switch or sound responsive device generallydesignated by the numeral 10 and comprising a support 11 secured to acircular base 12 as by a plurality of screws 13. Also secured to thebase 12 is a casing 14 for the switch, which casing is provided with acircular flanged portion 15 having a plurality of holes therein adaptedto receive the screws 16. A thin flexible diaphragm 17, preferablycircular in shape and of a material suitable for the pur pose such, forexample, as beryllium copper or sheet metal, is mounted between the base12 and the support 11 with suitable gasket means 18 arranged between thebase and diaphragm. The base 12 is provided with a recessed aperture 19which allows sound signals or pressure impulses to impinge against theouter surface of the diaphragm 17.

The diaphragm 17 and support l1 are provided with coincident apertureswithin which is disposed a mass or post 21 securely clamped to thediaphragm by means of a packing nut 22 screwed to a threaded extremityof the post 21, thereby causing the post to vibrate as the diaphragmvibrates. A suitable gasket 23 is mounted between the packing nut anddiaphragm to insure a watertight relation therebetween. It should benoted that the support 11 limits the vibrational amplitude of thediaphragm.

Secured to the support 11 by means of the screws 24 are two mountingstrips 25 and 26, each being electrically insulated from the other andfrom the screws 24 by a strip of suitable insulating material 27 such,for example, as rubber, Bakelite or the like, the strip 26 also beinginsulated from the support by an additional strip of similar insulatingmaterial. The mounting strip 26 has two upright portions 28 and 29, theportion 28 having a threaded hole therein adapted to receive theadjustable screw bearing 31, the portion 29 also being provided with athreaded hole therein adapted to receive the adjustable screw bearing32. A lock nut 33 is disposed around the screw bearing 32 formaintaining the bearing 32 in an adjusted position with respect to theupright portion 29.

Disposed about the screw bearing 31 is an internally bored, circularmember 34 and releasably clamped between the member 34 and support 28 bythe screws 35 is a ring member 36 having a relatively large insidediameter with respect to that of the member 34. Extending from themember 36 is an arm 37 which may be rotated to any desired setting byloosening the screws 35 and rotating the ring member 36. Secured to thearm 37 is a resilient spring 38 known in the trade as a hair spring, theother end of which is in engagement with a shaft 39. The shaft 39 istapered at the ends thereof and is mounted for rotation in the bearings31 and 32. An inertia member or light weight balance wheel 41 is securedto the shaft 39 and rotatable therewith. A long, resilient or Whiskertype electrical contact 42 is mounted on the balance wheel and isyieldably held by means of the hair spring 38 in continuous engagementwith another long, resilient or Whisker type contact 43 when the switchis in a state of rest. The contact 43 is aixed to the post 21 andinsulated therefrom by means of suitable insulating material 44, thecontact 43 also being arranged at right angles to the contact 42. Itwill be noted that the pressure between the contacts 42 and 43 ismaintained at a predetermined value by the tension of the hair spring 38in accordance with the setting of the ring member 36.

The conductor 45 is soldered to contact 43, thereby maintaining theconductor in electrical connection with contact 43. Similarly, conductor46 is soldered to the mounting strip 25, thereby maintaining conductor46 in electrical connection with contact 42.

A suitable cup-shaped cover 47 is secured to the support 11 by aplurality of screws 48, the cover having arranged therein a partition 49provided with a flanged portion 51 wherein a hole is drilled which isadapted to receive the post 21. ln the bottom of the cover are aplurality of holes through which the conductors 45 and 46 are passedwith encasing means 52 being provided fo-r each conductor. A suitablegasket 53 is mounted between the cover 47 and support 11, therebyinsuring a watertight connection therebetween.

The device is also provided with a rubber sack 54 arranged within thecasing 14, the sack being securely clamped between the base 12 and theflanged portion 15. Cut into the flanged portion 15 is an opening orport 55 which allows Water to pass into the space between the casing 14and sack 54 when the chatter switch is submerged, thereby deating thesack and causing the air enclosed thereby to be compressed. A hole 56 inthe cover 47 also allows the air within the cover to be compressed andby reason of a plurality of holes 57 cut in the support 11, theresulting air pressure is applied to the inner surface of the diaphragm17 to balance the water pressure on the outer surface thereof.

A housing S is secured to the casing 14, the housing having holes cut inthe top and bottom surfaces thereof through which the cable 59containing conductors 45 and 46 is passed. A plurality of holes are alsocut in the casing 14 to allow passage therethrough of the conductors 45and 46, with suitable encasing means 61 being provided at each hole inthe casing 14 and housing 58 to prevent leakage of water into thedevice. It will be noted that the sack 54 is securely clamped betweenthe housing 58 and casing 14.

A brief description of the operation of the present invention inconnection with submarine mines will now be given. Let it be assumedthat the chatter switch has been mounted on a mine casing 62 by means ofthe screws 16 and has been submerged in a body of water. Let it furtherbe assumed that the contacts 42 and 43 comprise a control circuit (notshown) for the mine carrying the switch and that the sensitivity of thecontacts has been manually adjused in order that weak sound signalsstriking the diaphragm 17 will not cause the contacts to be disengaged.Let it be assumed still further that the diaphragm 17 has been tuned toa frequency resident in the range of sound frequencies transmitted by asurface vessel moving within the vicinity of the switch.

When the switch 10 is submerged, the diaphragm 17 is subject to thepressure of the surrounding water and to compensate for this, the wateriiowing in the port 55 causes the rubber sack 54 to collapse partially,thereby substantially equalizing the pressures acting upon the inner andouter surfaces of the diaphragm, as heretofore described.

When a sound signal or pressure impulse of sufficient strength toovercome the pressure maintained between the contacts 42 and 43 by thehair spring 38 and of a frequency substantially corresponding to theinherent resonance frequency of the diaphragm 17 is transmitted throughthe surrounding water and impinges against the outer surface of thediaphragm, the diaphragm is set in vibration. When this occurs, the massor post 21 also vibrates by reason of the packing nut 22 which securesthe post to the diaphragm. As the post vibrates, the Whisker typecontact 43 carried thereby is caused to strike the resilient contact 42mounted on the balance wheel or inertia member 39 and cause the contact42 and balance wheel to vibrate thereby causing the control circuitcomprising contacts 42 and 43 to be interrupted at intervals.

In the event a countermining explosion occurs within the vicinity of theswitch and abnormally large amounts of acoustic energy resultingtherefrom strike the diaphragm 17, the resilience of the whisker typecontacts and the relatively light weight of the balance wheel providedin the switch of the present invention preclude the possibility ofdamage or operational impairment to these elements. Moreover, if thelcontacts are set in vibration vigorously, the arrangement of thecontacts at right angles to each other precludes the possibility of afailure thereof to close intermittently. It should be pointed out thatthe diaphragm 17 and mass 21, and the contact 43 and the inherent massthereof comprise a two mass vibratory system whereby the vibrationalamplitude of the contact 43 is greater than that of the diaphragm 17.

From the foregoing, it should now be apparent that a device has beenprovided which is well adapted to fulfill the aforesaid objects of theinvention. While the invention has been described with particularreference to an embodiment thereof which gives satisfactory results, itwill readily be apparent to those skilled in the art to which theinvention pertains, after understanding the invention herein described,that further embodiments, modilications and changes may be made withoutdeparting from the spirit and scope thereof, as defined by the claimsappended hereto.

The invention herein described and claimed may be manufactured and usedby or for the Government of the United States of America without paymentof any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. A device of the character disclosed adapted to be immersed in a bodyof water and comprising a casing having two openings therein andenclosing a space, a rigid support secured to said casing, a vibratorymember covering one of said openings and securely clamped between saidsupport and said casing, said support being adapted to limit theamplitude of vibration of said vibratory member, a pair of whisker typecontacts arranged at right angles to each other, inertia means securedto said support for pivotally mounting one of said pair of contacts,means including said vibratory member for vibrationally mounting theother of said pair of contacts, means settable at will for yieldablymaintaining said pair of contacts in continuous engagement when thedevice is in a state of rest, and a normally expanded, gas-filledcollapsible member over the other of said openings providing a chamberin communication with said space, said member being collapsible inresponse to water pressure when said deviceV is immersed in the water toforce the gas therein into said space, thereby to increase the pressureon the inner surface of said vibratory member for balancing the waterpressure on the outer surface thereof.

2. A device of the character disclosed adapted to be immersed in a bodyof water and comprising a casing having an opening therein, a rigidsupport secured to said casing, a vibratory member covering said openingand securely clamped between said support and said casing, a pair ofWhisker type contacts disposed in mutually perpendicular relation, meanson said support pivotally mounting one of said pair of contacts, meansmounting the other of said contacts for movement with said vibratorymember, means yieldably maintaining said pair of contacts in continuousengagement when the vibratory member is at rest and providing cycliccontact closure with the application of vibrational energy to thedevice, and means sealed in said casing for equalization of the internalpressure with increases of external pressures as the device is immersedin a body of water.

References Cited in the le of this patent UNITED STATES PATENTS2,396,672 Bancroft Mar. 19, 1946 2,396,699 Hayes et al. Mar. 19, 19462,401,934 Hester June 11, 1946

